接前一篇(2),还有个要求就是鼠标必须把起始点和和结束点放到道路上，或是是十分接近道路的地方，算是个缺憾吧
//求最短路径，得到路径长度，经过的道路的名称
function TfrmMapX.GetMinRoute(var RouteLength: double; var RoadNames: string): boolean; //求最短路径
var
routefea: CMapXFeature;
lyr: CMapXLayer;
begin
Result := False;
//验证
if uMrStartPt.RoadID <= 0 then
begin
ShowMessage('起始点没有在主要道路上');
Exit;
end;
if uMrEndPt.RoadID <= 0 then
begin
ShowMessage('结束点没有在主要道路上');
Exit;
end;
if uSeekRouteObj = NIL then
uSeekRouteObj := TSeekRoute.Create(uMrConn, Map1, uMrCroScope);
routefea := uSeekRouteObj.GetOptiRoute(uMrStartPt, uMrEndPt, RoadNames);
if routefea <> NIL then
begin
routefea.Style := uMrRouteStyle;
lyr := GetMarkLayer(uMrLyrNames[1]);
lyr.AddFeature(routefea, EmptyParam);
RouteLength := routefea.Length;
routefea := NIL;
Result := True;
end;
end;
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